If you listen to any health or fitness expert today, you’ve probably heard the term VO2 max tossed around. You’ve maybe even heard it from me. But to truly leverage it as a tool for your health, it helps to understand what it is, why it matters, and how you can actually change it.

What is VO2 Max and Why Should You Care?

Simply put, VO2 max is a direct reflection of your cardiovascular fitness. It is the maximum amount of oxygen your body can absorb and utilize during intense exercise. 

Often described as your body’s engine size, an athlete with a bigger engine (VO2 max) can comfortably maintain a much higher intensity than someone with a smaller engine. 

But this isn’t just for athletes. VO2 max is actually one of the single best predictors of health and longevity, outranking traditional factors like hypertension, diabetes, cardiovascular disease, smoking, and obesity! (1)

To say it simply, there is no upper limit on the benefits to being fit. The more fit you are, the lower your risk of mortality. 

Because of the potency of VO2, researchers have dug into many questions to guide protocols to improve it: How much exercise should I do? At what intensity? What should it look like?  Below is a brief overview of some foundational concepts. 

If you are new to exercise

First of all, if you are just starting your fitness journey, understand that anything is better than nothing. (2) Seriously, the research shows that any baseline increase in physical activity can trigger measurable improvements in cardiovascular fitness in as little as two weeks in untrained individuals. (3,4)

Great ways to start include:

• Take the stairs instead of the elevator
• Park further away in the parking lot
• Go for a dedicated walk daily
• Make a point to move for a few minutes every hour of the day. 

Does the type of exercise strategy matter? At first, NO! You get a significant health boost whether you do  steady-state exercise or high-intensity intervals (HIIT).(3,4) In my opinion, this implies you should do whatever movement you actually enjoy just to build the habit.

Once your habit is locked in, you can optimize your results using a more specific routine backed by science.

For the Average Exercising Adult

So, how would an average Jane or Joe improve VO2 max? Similar to before, any form of cardiovascular exercise tends to lead to improvements. For baseline health, the current recommendation is a weekly minimum of 150 minutes of moderate-intensity cardio or 75 minutes of vigorous exercise (this is nuanced!). However, to maximize your cardiovascular gains, the data suggests aiming to include a 4- to 12-week program that features high-intensity working intervals (2 minutes or longer) that add up to more than 15 minutes of total hard work per session.(3,4) This is termed High Intensity Interval Training (HIIT).

Here is a classic example of a protocol with those parameters: 

The 4×4 protocol

• Frequency: 2 times per week.
• 4 minutes of high-intensity exercise (breathing heavy, hard to talk
• 3-4 minutes of easy recovery (i.e. light walking)
• Note: This equates to 16 minutes of total working time

For the Elite Athlete

For high level competitors, moving the needle is much more challenging, and the science behind it is more complicated! This is due to the fact that many elite athletes are already operating right at the edge of their genetic and physiologic potential.5,6 To say it simply, they have maximized their “gains”. 

Also, VO2 max is just one of the many aspects of sports performance, and improving it doesn’t always translate cleanly to competitive performance.(5,6) Thus, if you are an elite athlete, my first recommendation is to work with a certified coach or specialist. 

That being said, below are some general principles to consider for improving VO2 max in the elite. 

What doesn’t appear to work? 

Elite athletes seem to get no significant improvements in VO2 max from moderate-intensity steady-state workouts, nor do they see significant VO2 max improvements from short sprint interval training. This is likely due to the lack of stress on the aerobic system needed to promote adaptation.(5,6)  

On the other hand, running intense interval blocks for longer than ~8 weeks overtaxes an already highly adapted system, leading to diminishing returns and potential overtraining (5,6)  

So, there appears to be a more delicate balance when it comes to improving VO2 in highly trained athletes vs. untrained. 

Concepts for the Elite Athlete 

To force an advanced cardiovascular system to adapt, the current evidence (5,6) suggests these concepts to improve VO2 max:

• Keep the blocks short: Stick to a ~ 4 to 6-week training block to avoid overtraining  
• Stay specific to your sport: If you are a runner, run; if you are a cyclist, bike.
• Time it for the season: Do the block during your competitive season, and do the intervals in addition to your conventional training. 5,6 
• Longer intervals for aerobic adaptation: Focus on traditional, long intervals (2 to 4 minutes of sustained effort).  
• High intensity: The working intensity must be near-maximal for the amount of time given.  
• Rest easy!: Rest for 2 minutes or longer between intervals, and keep it incredibly easy.

Remember, these are just general guidelines, and they should not take the place of an individualized program. I highly recommend working with a professional when it comes to navigating your unique health journey! If you find this interesting and want to continue the conversation, please reach out to me at bill@shoreuppt.com.

Sources:

1. Mandsager K, Harb S, Cremer P, et al. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw Open. 2018.
2. Taylor T, West S, Benson M, et al. The effectiveness of exercise snacks as a time-efficient treatment for improving cardiometabolic health in adults: a systematic review and meta-analysis. Front Cardiovasc Med. 2025.
3. Milanović Z, Sporiš G, Weston M. Effectiveness of High-Intensity Interval Training (HIT) and continuous endurance training for VO2max improvements: a systematic review and meta-analysis of controlled trials. Sports Med. 2015.
4. Wen D, Utesch T, Wu J, et al. Effects of different protocols of high intensity interval training for VO2max improvements in adults: a meta-analysis of randomised controlled trials. J Sci Med Sport. 2019.
5. Rosenblat MA, Lin E, Da Silva DF, et al. Comparison of polarized versus other types of endurance training intensity distribution on athletes’ endurance performance: a systematic review with meta-analysis. Sports Med. 2024.
6. Zhao K, Ma S, Han T, et al. VO2max (VO2peak) in elite athletes under high-intensity interval training: a meta-analysis. Front Public Health. 2023.